Ciao Heru (cc Lydia)
You dont need have a program or something, is very easy as of now, it's automatic, you have two options:
1. open the ky page, click "Save as" under File tab. In firefox browser there are 4 items on which format to save, better take HTML in full format. And you only need a browser to open it, even in offline mode (no internet required).
2. If you want the pdf instead, opne a ky page, click "Print" under File tab. A new window will come up where there are printing options such as colors etc, forget about it, just look at the drop down menu on the bottom left, where there is a "Save as PDF" option. Just click it and will open a new window where it asks you where you want the file saved (in a folder or desktop or etc.), then click SAVE button. And voila you have the pdf file automatically and with images already placed.
I'm talking all from MacOS user. If you use Windows or Linux, should be a little bit different things, but definitely the items like "print", then "save as pdf" is there, search, maybe it's in a different position of the window/tab or things like that.
Both 1 and 2, the only boring stuff is that you have to organize the various pdfs/htmls, sorting them so the reader can navigate between the files.
Lastly, there is always the archive site (archive.org) there are ToZ pages there for years and they are not removed. I read a while ago that someone says they remove but I don't have proof by hand. So.
Ciao!